Done a lot of searching here re using a v tail mixer with differential throttle but can't find an answer.
Using just the v tail mixer only (without any Tx mix) for rudder & throttle is going to give this mix in the air as well as when taxiing, which might be OK for experts but not me

Is this the only application for a v tail mixer?
I'm assuming The Tx program mix is not used in conjunction with a v tail mixer. Is this correct?

Done a lot of searching here re using a v tail mixer with differential throttle but can't find an answer.
Using just the v tail mixer only (without any Tx mix) for rudder & throttle is going to give this mix in the air as well as when taxiing, which might be OK for experts but not me

Is this the only application for a v tail mixer?
I'm assuming The Tx program mix is not used in conjunction with a v tail mixer. Is this correct?

Kev

Correct when using an external mixer the TX needs no mixing. When using an external mixer the rudder will stay as rudder into the mixer and will need a 'Y'' lead from the RX, one side into the mixer the other to the rudder servo, then the elevator input will be connected to the throttle on the RX instead of elevator and the 2 outputs from the mixer will be connected to the throttles. If the motors pull the wrong way swap the throttle leads over at the mixer. With this setup the rudder response may become very sensitive as the motors are mixed all the time so be aware you may need to dial down the rudder endpoints. A cautious test flight will be needed as full rudder may cut the one throttle and firewall the other.............be careful

To do the diff' throttle from the TX you need to have a TX with 3 free user defined mixes on it, a lot of middle range TX only have 2.

You then split the throttle cables to throttle and a spare channel lets say aux 1

Then you set a mix using throttle as master and aux 1 as slave and set that up so both throttles work together.

Then set a mix with rudder to the right as master and your right motor channel as slave so that the right motor reduces throttle when right rudder is applied.

Then set a mix with rudder to the left as master and your left motor channel as slave so that the left motor reduces throttle when left rudder is applied.

These last 2 mixes can be set to be activated by the same switch, you can then turn it on and off as you wish or programe that it only becomes active above a very low throttle setting so you can taxi fine and then the mix cuts automatically. Different brands have different programming methods so this is just the outline of what you need to do.

Test each stage as you do them to confirm it does what you want.

Then double check everything once finished, make sure both throttles increase and decrease in sync and there is no reduction in full throttle.

It would be a good idea to check rpm with a tacho.

When first flying check again with a taxi test to confirm correct function of the mixes.....get it wrong and its gonna end badly.

Dave

PS dont use it myself as I find that unless its real windy( I fly something else) I can taxi with rudder

**********WARNING IF IN DOUBT DONT DO IT, GET IT WRONG AND ITS UGLY************

Correct when using an external mixer the TX needs no mixing. When using an external mixer the rudder will stay as rudder into the mixer and will need a 'Y'' lead from the RX, one side into the mixer the other to the rudder servo, then the elevator input will be connected to the throttle on the RX instead of elevator and the 2 outputs from the mixer will be connected to the throttles. If the motors pull the wrong way swap the throttle leads over at the mixer. With this setup the rudder response may become very sensitive as the motors are mixed all the time so be aware you may need to dial down the rudder endpoints. A cautious test flight will be needed as full rudder may cut the one throttle and firewall the other.............be careful

To do the diff' throttle from the TX you need to have a TX with 3 free user defined mixes on it, a lot of middle range TX only have 2.

You then split the throttle cables to throttle and a spare channel lets say aux 1

Then you set a mix using throttle as master and aux 1 as slave and set that up so both throttles work together.

Then set a mix with rudder to the right as master and your right motor channel as slave so that the right motor reduces throttle when right rudder is applied.

Then set a mix with rudder to the left as master and your left motor channel as slave so that the left motor reduces throttle when left rudder is applied.

These last 2 mixes can be set to be activated by the same switch, you can then turn it on and off as you wish or programe that it only becomes active above a very low throttle setting so you can taxi fine and then the mix cuts automatically. Different brands have different programming methods so this is just the outline of what you need to do.

Test each stage as you do them to confirm it does what you want.

Then double check everything once finished, make sure both throttles increase and decrease in sync and there is no reduction in full throttle.

It would be a good idea to check rpm with a tacho.

When first flying check again with a taxi test to confirm correct function of the mixes.....get it wrong and its gonna end badly.

Dave

PS dont use it myself as I find that unless its real windy( I fly something else) I can taxi with rudder

**********WARNING IF IN DOUBT DONT DO IT, GET IT WRONG AND ITS UGLY************

Thanks Dave. Kind of you to go to that trouble
I was very interested to learn you don't use it! Think I'll do the same!
I can see it as complicating things quite a bit.

So the water rudder is OK except for windy days eh? Well can't see myself flying in wind because the water would also be choppy. I will be flying on the bay here and even light wind makes it very choppy.

Thanks Dave. Kind of you to go to that trouble
I was very interested to learn you don't use it! Think I'll do the same!
I can see it as complicating things quite a bit.

So the water rudder is OK except for windy days eh? Well can't see myself flying in wind because the water would also be choppy. I will be flying on the bay here and even light wind makes it very choppy.

Cheers

Kev

No sorry, I dont use the water rudder either, I never fitted it cos it looked awful.......

After having the kit for close to 1/2 a year I finally put it together and maidened it off the water with success!!!! But not without an issue though. The tail is very crooked on the back of the plane and the end result is it taxis very hard to the left. Enough to make it almost loop around. I have to trim the rudder all the way to the right to combat this. This makes for a tough setup with the differential throttle now being trimmed and now when I taxi I can only turn 1 way more than the other. Sucks! But luckily I only taxi for a short time and line it up into the wind and turn off the diff throttle and take off. The plane flies very well, its a bit tricky to figure out the CG on it IMO, I had it on my CG machine and it just doesnt want to seem to find that sweet spot. I had it set to 70mm and it still was a bit tipsy either direction. But nothing a little trial and error cant fix. The elevator is also very sensitive, I took the advice given on here and dropped my elevator throw from 70% to 55%....MUCH BETTER on takeoffs. If its a tad tail heavy, which it was, and if you take off off in a scale manner with 50-70% speed, which I did, and if you pull back harder than you think its going to pull, which I did, you could end up stalling it pretty quick.....which I ALMOST did. I saved it with a quick throttle up and fought it.

Another issue I just encountered is I was flying at the park, takes off beautifully from the grass by the way!!!!!!!! and I lost power to the motors and I had to make an emergency landing. 1 or both ESCs were beeping 2 beeps, then 1 beep, continually. I had no power to the 1 motor and it kinda just twitched. I thought maybe it could be the LVC kicking in. Nope, the battery was fine when I checked it. I tried to power it up after that with the same battery and a different battery and both resulted in 1 ESC not arming, but after a few seconds it would run like normal. I uplugged and plugged back in several times, still the same. Then I decided to go to the RX and uplug both ESCs and plug them back in. Now it works like nothing happened, both arm up normally. What could be causing this? I am running alpha 370 motors, 30a plush escs, 1 2200 lipo, the recommended mini/micro servos and a 9X Tx with the FrSky tx mod and a 8 channel rx. I have diff throttle setup as well. I also disconnected 1 red wire on 1 ESC when plugging it into the RX. I havent noticed if the motor that was acting up was the one with the ESC having a red wire or the one that is disconnected, I will take a look tonight to see. Any thoughts?

I did fly from water earlier that day, almost 4 hours before, and might have gotten it wet. But does that explain the "reboot" and why that worked? Meaning, does it either fry or have to be rebooted if it gets wet?

getting these ESCs wet can cause some odd things, could have just dried at the same time as you were checking, or you could have disturbed some water.

I have my ESCs in party balloons on both my seaplanes and had hundreds of flights since then with no trouble.........it took about 10 flights for my Catalina to get an ESC wet enough to give the random beeping.

However if you were talking about a normal plane with no water involved the symptoms sound like one ESC not being quite at full low throttle, it only needs to be one click of trim out and it wont arm, drop the throttle trim right back (if its the motor on throttle channel, if not use sub trim on the other) and try like that or if you have endpoint adjustment on the channel that the ESC thats playing up is on wind in a bit more travel on the low throttle side.

The addition of the differential throttle mixes caused some fine adjustment on my Futaba TX/Spektrum module. I had to use offset get the motors to start together and sub trim to get them to throttle up and down at the same speed bu at some points the one motor stops and the other is just starting and it wont arm like that, give the tx a knock or reboot lipo connection and all is fine. Adjust the endpoints down and now will start every time.

Dave

PS I dont use diff' throttle usually as both my CL and cat turn fine without(just needs bursts of power to get the air rudder working as I dont use water rudder either) but set it up to show someone the mixing on here to help them out.

Flew it again today, no problems at all. That 1 motor dying with esc beeps is even more bothersome now that I cant recreate it. Aside from problem solving that issue the plane flew amazing. Grass take offs are a real treat, I actually used a chassis guard (thick protective sticker sheet) and put it on the bottom of the plane to avoid getting dinged up just in case I land on a rock and also it will be ready for the winter to land on ice and snow. It takes off straight as an arrow and is a such an awesome gentle flier. I experimented a bit with the throttle and stalling, it can be flown really slow but you gotta watch your turns, just like in the above video. Landing it was a piece of cake, the grass really grabs a hold of it once you grease it in. Do I dare say this plane is more fun in the grass than the water???? You dont have to worry about the chop, you dont have to worry about water proofing, you dont have to worry about the tip floats getting caught on a wave......this plane is sooo awesome.

I did a test and I am pulling 24 amps and 240 watts on full throttle. Running 8x6x3 props. A 2200mah battery sure doesnt last very long flying at about 3/4 throttle. Is there another 3 bladed prop thats more effecient? 9" perhaps? Or change the pitch?